This is a continued open label investigation of the safety and toxicity of the agent recombinant methionyl human brain-derived neurotrophic factor. The primary goal of this work is to determine the long-term tolerability and safety profile of daily subcutaneous administration of recombinant human brain-derived neurotrophic factor in patients who have completed all study treatment requirements in previous trials with R-methubdnf without evidence of intolerable toxicity.